Removal of wax from hydrocarbon oil



Patented Mar. 19, 1935 g i I UNITED. STATES T N Meet- Bernard Y. McCarty, Beacon, N. Y., and William E. Skelton, Cambridge, Mass, assignors to The Texas Company, New York, N. Y., a corporation of Delaware I v No Drawing. Application November 30, 1931,-

' Serial No. 578,206 1.

6 Claims. (01. loo- 19) "This'invention relates to theremoval of'wax thereby tend reduce the filtering ate o from hydrocarbons and more particularly to an a pointYwthere the operation is not economical. improved process for the removal of paraffin from In addition; the" presence of this separated liquid lubricating oil fractions derived from petroleum, gives rise to 94 C nd o Whichis predlletiveilpen 7Y The invention contemplates aprocess or dewaxfiltration Q e W cake: Containing Substantial 5. ing wax-containing lubricating oil fractions by n s, of Oil that h a i Yield of filtration at low temperatures, wherein the wax; dewaxed' oil is not realized. v I 1 containing oil is mixed withja Wait -precipitating It is essential that such a solvent'mixture reliquid mediumcomposedof a solvent liquid or main completely homogeneous at these loWtem-' m mixture of solvent liquids which is, completely p es d' t exhibit y nd y for a y 10 miscible with, and exerts a substantially complete of its components to separate from the mixture, solvent action upon, the oil at the temperatures pon Separation of one-of the co p v at which the wax constituents'are precipitated the olv t mixture, the ratio of the components from the oil in solid form and which has substanremaining in the mixture iS d, t y tially no solvent action on the solid hydrocarbons a ing its se c t' p 0 at 15 at uch temperatures Th resulting i t i the wax constituents will not be completely prethen chilled to precipitate the solid hydrocarbons -oipitate e /o app ci a ts r the iqwhich re remo d by filtrationf uid-hydrocarbon may separate from the solution More specifically the invention contemplates due to he r tin a k of pl t is i i ty g mixing with lubricating oil fractions a wax-pre- Oh h D 0f the S l h the Oil gt cipitating liquid medium composed. of a mixture t dn i U of. ortho-dichloro-benzene with either ainyl al- Extensive inv t on has demonstrated that cohol', diethyleneglycol-mono-butyl ether, methyl a Solvent l q i s lv 'm 're t y ethyl ketone, propylenev dichloride or ethylene fOT e a WeXsDTeeiDitetihg d u in the 5 dichloride. In some instances, ordinary commer deWeXihg 0f wexj-eehteining"hydrocarbon cialbenzene may be used as in the case of mixustp ss s am t r t s; w a s lut tures with th ether compound, I viscosity and low viscosity temperature coefii- An object of thi in ention i t efiect d cient, high oil solubility at low temperatures, low waxing of paraffin-containing hydrocarbon oils Solubility at ow temperatures, W freezing with an improved type of solvent liquid composed point, and also p s ss t p p r y f p p- '30 of a mixture of solvents having selective solvent itating WaX in a readily fi e ab Co d t onproperties between the oil and the wax constitu- Accordingly after investigating varioussolvent ents and which, in addition, retains its selective liquid mixtures, it has been found that a mixture solvent properties at relatively low temperatures f, r h -d chl oand y eleehei,

whereby, the precipitation of the wax from the, hylene-s yc yl he p p e e, o as mixture, particularly in the case of mixtures with ethylene dichloride, possesses the foregoing comrelatively viscous oils, is effected in ar'nore readily bination of p p thereby rendering t Su-' filterable ioi-m. At the same'time, athigh yield p ior to the so vent liqui or liqu d mixtu s of dewaxed oil is obtained hitherto used in the art and, therefore, partic- 40 A further object has been to develop a solvent l 'ly W d pt 94$v -p p e .40

liquidwhich' possessed the foregoing properties medium'for' use in'th'e manufacture of-loW 1 at relatively low temperatures and which is, there test'paraffin base lubricating oil. The relative fore, adaptable for the manufacture of lubricatp po on of the l q ds to each other, as w ing oils having pour tests of -20 F. and lower. as that of the resulting solvent mixture to the A selective solvent suitable for the foregoing oil, may be varied as desired, depending upon the 45 dewaxing operation, and particularly when com-' nature of e i undergoing treatmentposed of two or more organic solvents, must re- Y s ,W n deWeXing a lubricating d stillate tain its homogeneity andits property of remainac ion, having a visc s y around 0 to 80 I ing completely miscible with the liquid hydrosaybo t universal s s or higher t 210 F-,

, carbon constituents of the mineral oil at teiny y Parts Of the Oil may be mixed With 50' V peratures substantially well below 0 F., Comabout seventy pa of a S en ixtureco plete miscibility is necessaryin order to prevent posed of around20% ortho-dichloro-benzene and separation of such liquid hydrocarbons from the about 80% of commercial ad a yl al ol, solution; Such separated liquid hydrocarbons The resulting mixture is then chilled to about 51$ materially increase the viscosity of the solution '10 F. or to a temperature corresponding sub- 55 stantially to the desired pour test of the resulitng dewaxed oil, following which it is subjected to filtration while still maintained in a cold condition to separate theprecpitated wax constituents. Advantageously filtration may be carried out in the presence of a finely divided comminuted filter-aid material which may be added to and commingled with the cold mixture of oil, solvent and suspended wax crystalsl. After removal of. the solvent liquid from the filtrate, the resulting'lwbricating oil will have a pour test of 0 F. or lower.

Similar results may be obtained, onthe other hand, by mixing the oil in about the'same pro portion with a solvent mixture composed of about ortho-dichloro-benzene and about 35% of either ethylene or propylene dichloride.

It is frequently desirable to employ a solvent. liqe. uid mixture in which the benzene is.at,least. r

the ethylene orpro-" distillate fractions but maygalso be used in dewax- 30 nag-various wax-bearing fractions of mineral oil. Obviously many modifications and variations of. the invention, as hereinbefore set forth, may

be made without departing from the spiritand scopethereof, and-.therefore-only suchlimitations should be imposed as are indicated inthe appended. claims We claim: v

I. In a process of separating wax from a Waxbearing mineral oiltoproduce low pour testglubrireating oil, the step comprising mixingwith the oil :a wax-precipitating liquid medium composed of-ortho-dichloro -benzene in admixture with a liquidselected fromthegroup consisting ofethyl ene dichloride and propylenedichloride in such 0' proportions thatat temperatures of the. order of l0f F..; the mixture has substantially complete solvent action on the oi1Y. d,,Substantia-llyno, solvent action on the wax.

t 2. In the process of separating waxfroma waxcontaining lubricatingv oil fraction, the stepcomprising mixing with the fraction a waxrprecipitating liquid medium composed of ortho-dichlorbenzene and ethylene dichloride in: such proportionsthat at temperaturesotthe order-of I0 F.

the. mixture has substantiallyi complete. solvent action on the oiland substantially no solvent ct on o h w xj r I v .3. In theprocess-of separating wax from a wax-containing ubricating oilfraction, the step comprising mixing with the fraction. a waxprecipitating liquid medium composed of orthodichloro-benzene and propylene dichloride, in such proportions that at temperatures of the order of ,-l0 F. the mixture has substantially complete solvent action on-the oil and substantially no solvent action on the wax.

4. The process of dewaxing wax-bearing mineral oil comprising mixing with the oil a selectivesolvent liquidcomposed of ortho-dichlorobenzeneand a'liquid selected from the group consisting of ethylene dichloride and propylene dichloride in such proportions that at temperatures 7 of the order of -10 F. the mixture has substantially complete solvent action on the oil but substantially no-solvent action on the wax, chilling the mixture to precipitate the wax, separating thewax thus precipitated, and removing the solvent from the dewaxed oil.

5. The process of manufacturing low pour test lubricating. oil from Wax-bearing lubricating-oil fractions byfiltrationat a temperature substantially the. same as the ,pourtest of. the desired product, comprising mixing. with the wax bearingfractionra wax-precipitating liquid mediumcomposed .of 'ortho-dic'lfloro b'enZene and a, liquid selected'. from .the group consisting of ethylene dichlorideand propylene dichloride inv such proportions that, at temperatures of the order of l0 F. the mixture has substantially. complete solvent. action on the oil and substantially no solvent action' on the was, chilling, the mixture.

to. a temperature corresponding substantially to thepour .test .of the. desired product in order to precipitate the wax constituents, andjfilteringthe mixture'whilemaintained in. .a cold, condition to 0 remove the precipitated wax constituents and produce a desired low pourftestlubrioatingvoil product f H 6.: The process of manu'facturing low pour. test lubricating oil from wax bearing lubricating" oil A fractions by filtration at, a temperature substan-. tially the same as the pourtest of thedesired product, comprising mixing with the wax-bearing fraction a wax-precipitating liquid mediumcoinposedcf ortho-dichloro-benzene and a liquidsee lected from the group consisting of ethyl'e.n'e.oli chloride, and propylene dichloride insuch proportions that at temperatures of the order of. "l0 F. the mixture hassubstantially complete solvent action on the oil and substantially'no solvent action on the wax, chilling the mixture, to a temperature corresponding substantially to the pour test of the desiredproduct in order to-precipitate the wax constituents, and'filtering the mixture'in the presence of a filter-aid material while maintained in acold condition to remoLve the precipitated wax constituents and produce a desired low pour testlubricating oilproductf BERNARD McCARTY..' WILLIAM E. SKEL'ION'.. M 

